Gold Bar wastewater treatment plant gets top marks

Edmonton's Gold Bar wastewater treatment plant, considered one of the best by Environment Canada, has drawn experts from across the country seeking to learn how they can improve their own facilities.

Located on 19.5 acres of land in east Edmonton on the south bank of the North Saskatchewan River, the Epcor-owned tertiary treatment plant treats about 310 million litres of sewage a day and about 100,000 million litres annually, which is enough to fill 37,000 Olympic swimming pools per year.

Edmonton received an A+ on a national sewage report card issued in 2004 by Ecojustice, a non-profit group devoted to protecting the environment. Calgary was the only other Canadian city to earn an A+.

While it's part geographics and part rich oil heritage that help pay for the necessary infrastructure and upgrades, there's more that makes the Gold Bar plant a world-class facility, says Vince Corkery, director of Edmonton's wastewater treatment plant.

"Our regulators, the city of Edmonton and Alberta Environment, hold us to a higher standard than other plants would be held to," said Corkery, who's been with the plant since 1994.

"It's also the partnership with utility rate payers, who have to be mindful that high treatment standard comes at a cost."

Opened in 1956, the plant was already considered the most advanced wastewater treatment plant in western Canada. Built to serve a population of 25,000, the plant had 65 staff members on board, and consisted of one grit tank, two primary clarifiers, four digesters, three secondary aeration tanks, four sludge storage lagoons, a blower and boiler building, and administration building with a laboratory.

Over the last few years, the staff grew to a team of 140, and more than $200 million was spent on expansions and upgrades, such as replacing chlorine with ultra-violet technology. The plant now serves more than 820,000 people in Edmonton, Leduc, Beaumont, and Nisku.

Construction is on-going, about $30 million of work per year, with plans to add more tanks and improve odour controls. And while 15% of the city's system is still combined sanitary and storm water, plans are in place to eventually move to a separated system.

Corkery said the plant is not only a leader in water treatment but in water conservation, and in treating overflow stormwater in heavy rain situations, of which up to 90% is purified before being released back into the river. In many other cities, stormwater overflow is collected and dumped untreated into bodies of water.

The Clover Bar biosolids facility has also made strides in its treatment and reuse of biosolids, much of which is converted into composting or fertilizer for farmers' fields.

To ensure the treated water is up to standard, regular bio-assay testing is undertaken, which means fish are placed in samples of treated water for observation and then removed.

And while the Gold Bar facility does not produce potable water, "I guarantee there are people elsewhere that are drinking worse," Corkery said.

About $127 million, from utility costs and not tax dollars, will be spent to operate the facility this year, with services covering the collection of wastewater from the household at the property line and taking it through 3,500 km of piping to the treatment plant before it's discharged back into the river.

The average residential customer generates about 17.5 m3 of wastewater and pays about $317 per year.

The city's decision to sell the plant to current owner Epcor last year, a deal estimated to be worth $190 million over the next decade including a $75 million transfer fee and dividend payments, drew the ire of activist groups who raised concerns about privatization and the lack of public oversight.

But city officials argued that the move would allow the city-owned company to expand its wastewater business outside of Edmonton.

The city retains ownership and management of the wastewater collection system, pump stations, manholes, storm water ponds, and the Clover Bar lagoons.